Capitalize return a copy of the input string with the first rune uppercased.

Split behaves like strings.Split() expect it returns an empty slice if s is an empty string.

SwapCase returns a copy of the input string with rune case swapped.

SwapRuneCase returns a uppercased rune for a lowercase rune, or a lowercased rune for a uppercase rune.

TrimLast returns the string truncated of its last n runes.